Polishing small defects in the painted surfaces of automotive and other vehicles is a critical operation. Often vehicle surfaces are compromised during the painting process, and cars with visible scratches are not acceptable. There is no exact science to achieving an acceptable result other than providing a skilled operator with an air polisher and a pad. Polish is applied to the pad, the trigger is depressed, and after a few seconds the scratches usually go away.
There are basically two different types of paint polishers or buffers: rotary and orbital. Rotary units are still the most popular, as they are very effective at removing deep scratches, and overall paint polishing. However, these machines can remove paint from a vehicle very quickly, requiring careful use of the variable speed control. Orbital polishers, which operate by oscillating numerous times per second in pseudo-random directions, are a safer option for painted surface buffing.
Regardless of the system used, new paint system chemistry is making vehicle surface polishing much more difficult. In particular, new paint is harder and it takes longer to remove the defects. If more aggressing procedures are used the process can “go too far” and remove too much of the painted surface.
Lighting of the surface to be polished or buffed is therefore extremely important. In particular, correct color temperature for surface lighting is essential to providing an accurate representation of “true color” and surface condition. If a light source casts a wavelength other than “pure white” onto a painted surface, the true color and condition of paint defects cannot be accurately perceived. As such, color temperatures of about 4500 deg. K or below are undesirable for surface polishing, since warm tones of light are cast onto the surface. Thus, while incandescent lighting, in the range of 2700K-3300K, provides warm tones for household environments it is a poor choice for surface detailers. Halogen light at ˜2700K is one of the worst sources for bringing out painted surface defects, and while compact fluorescent lighting CFL at ˜2700-4200K is better but it can still generate undesirable color tinting.
Lighting at color temperatures between 5000K-6500K is much better at showing defects and flaws in painted surfaces, since this range is closer to sunlight. While light at 5000K is better at identifying true color since it is closest to “pure white,” the intensity of light at 6500K is often better at revealing surface conditions and flaws. However, a 6500K light will appear significantly cooler or bluish. Indeed, it has been found that light of around ˜5600K is considered a standard for observing the true color and condition of painted surfaces.
While there are power-driven polishers with means for illuminating the work surface, such devices are not intended for painted surfaces, nor do they provide an appropriate light source. U.S. Pat. No. 2,778,043, for example, describes a motor-driven polisher for shoes including a rotary brush extending from a hand-held housing. The housing includes a downwardly opening light bulb shield. The bulb “could be a flashlight bulb or the like,” and is engageable in a bulb socket that is mounted in confronting recesses formed in portions of the housing. Clearly such apparatus would not be suitable for polishing or buffing modern painted vehicle surfaces.